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This study evaluated the effect of ingesting a flavonoid-rich supplement (329 mg/d) on total urine phenolics and shifts in plasma metabolites in overweight/obese female adults using untargeted metabolomics procedures. Participants (N= 103, 18–65 y, BMI ≥ 25 kg/m2) were randomized to flavonoid (F) or placebo (P) groups for 12 weeks with blood and 24 h urine samples collected prestudy and after 4 and 12 weeks in a parallel design. Supplements were prepared as chewable tablets and included vitamin C, wild bilberry fruit extract, green tea leaf extract, quercetin, caffeine, and omega 3 fatty acids. At 4 weeks, urine total phenolics increased 24% in F versus P with similar changes at 12 weeks (interaction effect, P= 0.041). Groups did not differ in markers of inflammation (IL-6, MCP-1, CRP) or oxidative stress (oxLDL, FRAP). Metabolomics data indicated shifts in 63 biochemicals in F versus P with 70% from the lipid and xenobiotics superpathways. The largest fold changes in F were measured for three gut-derived phenolics including 3-methoxycatechol sulfate, 3-(3-hydroxyphenyl)propanoic acid sulfate, and 1,2,3-benzenetriol sulfate (interaction effects, p≤ 0.050). This randomized clinical trial of overweight/obese women showed that 12 weeks ingestion of a mixed flavonoid nutrient supplement was associated with a corresponding increase in urine total phenolics and gut-derived phenolic metabolites.

The purpose of this investigation was to assess the effect of resistance exercise performed to volitional failure on ratings of perceived exertion (RPE) using power as an indication of fatigue. 12 male participants (Mage= 21.9 yr., SD= 1.3) performed one set of back squats at three different intensities (50%, 70%, and 90% of one repetition maximum) for both a pre-determined number of repetitions (3) and to volitional failure. RPE was significantly different between sets at 50%, 70%, and 90% when performed to a pre-determined number of repetitions, but not during volitional failure. A decrease in power between the first and the last repetitions in the volitional failure sets suggests that fatigue may confound the relationship between RPE and intensity.